Automotive Air Conditioning Information Forum

Tim wrote:When it is not working well is when you need to get some pressure readings.

This would have been a good thread for GMtech. But have not seen him around in a while.

Tim, all of my gauge readings I've posted in this thread have been when "its not working well."

This is the last readings see posted. If charged properly charged, you might try a new CV. High is low and low is high. Personally I would not try a different color. What I see is you're not pulling down the low side very well. 34 psi is what one expects to see at idle, not 1500.

Cold engine

Idle.................................1500rpm
H135................................H155
L32..................................L34
Vent83F............................81F


Engine warming up but still not hot

Idle.................................1500rpm
H180................................H190
L34..................................L32
Vent78F............................78F

Thank you, Tim. It sounds like you and Al9 both recommend changing the purple control valve. Since I've got to open up the system anyway, another inexpensive item to replace is the OT. Would you recommend I do that as well or not?

Since it is open, sure.

Hey guys. I know it's been a long time since I've posted. I was out of town on vacation visiting family out east and when I got back, I started trying to learn how to MIG weld. Anyway, our north Houston mornings have been cool but our afternoons are still in the mid to upper 80s so not having working ac is still a big issue!

I do have a new control valve and a new orifice tube. I looked at the compressor both from the top and from the bottom. I couldn't see any control valve. I've looked at pictures of the Delphi compressor and it doesn't appear that the control valve is on the rear of the compressor either. I'm assuming that the CV is on the engine block side of the compressor and I'm going to have to remove it completely from the car. Does that sound right?

Thanks, guys and I promise not to let over 3 weeks go by again without updating this thread.

I crawled under the car yesterday and looked at the compressor from below. It was just the smooth metal body of the compressor. On the topside, it was the same. At this point I have to assume that I'm going to have to unbolt the compressor from the engine and look to see if the control valve is on the side of the compressor facing the engine.

The image in this link shows the location of the Control Valve.

https://ackits.net/product/14-20730nc/

Tim wrote:The image in this link shows the location of the Control Valve.

https://ackits.net/product/14-20730nc/

Thank you, Tim!!! I haven't been able to see that "view" of my compressor so it must be facing the engine.

I thought I was going to have plenty of time to work on this but now it looks like I won't be able to spend any time on it until early next week. I'll let everyone know once I've replaced the two parts.

I strongly recommend you pull the compressor to do any control valve swap.

Cleanliness is very important at that point. You want to clean the road grime off of the case around the valve assembly before you start.

Once you pull the snap ring, clean thigs again before you pull the valve out. Dropping a few grains of sand in the hole as you extract the valve can have consequences later...

Thank you for that advice, bohica. Once I realized that the valve is on the engine block side of the compressor, I figured that I'd have to pull the compressor out of there.


BTW guys, do you think that I should add any PAG oil to the system when I put it all back together? When I recovered the refrigerant, I didn't follow the Mastercool instructions to separate out any recovered oil. My machine's oil tank had no separated out oil. I think that someone at the beginning of this thread gave an estimate of how much oil would be lost during recovery.